1. Field of the Invention
The present invention relates to a mower comprising:
a chassis, PA1 a connecting means allowing the said chassis to be connected to a motor vehicle, PA1 at least one harvesting mechanism equipped with cutting members, PA1 a suspension device connecting the said harvesting mechanism to the chassis and allowing the said harvesting mechanism a heightwise movement with respect to the said chassis, PA1 a lightening device associated with the said harvesting mechanism and comprising two elastically deformable members extending transversely to the direction of forward travel during work, each elastically deformable member acting, via a first of its ends, on a corresponding end of the harvesting mechanism via a load-transmission member converting the transverse load created by the said elastically deformable member into an upwardly-directed load at the harvesting mechanism, PA1 a centralized device for adjusting the lightening force exerted on the said harvesting mechanism, the said device being coupled to the second ends of the said elastically deformable members. PA1 the said means converting the rotation of the rotary control member into an action of stressing or relaxing the elastically deformable members may comprise a rotary control-transmitting spindle fitted between the second ends of the elastically deformable members; PA1 the rotary control-transmitting spindle and the two elastically deformable members may extend at least approximately horizontally; PA1 the rotary control-transmitting spindle and the two elastically deformable members may be at least approximately parallel; PA1 viewed along a longitudinal axis of the rotary control-transmitting spindle, the said longitudinal axis and a longitudinal central axis of each elastically deformable member may be arranged at the three vertices of an at least approximately isosceles triangle; PA1 a longitudinal axis of the rotary control-transmitting spindle and a longitudinal central axis of each elastically deformable member may extend at least approximately in one plane; PA1 the means converting the rotation of the rotary control member into an action of stressing or relaxing the elastically deformable members may additionally comprise at least two cylindrical gear wheels at the second end of at least one of the elastically deformable members; PA1 the means converting the rotation of the rotary control member into an action of stressing or relaxing the elastically deformable members may additionally comprise at least two sprockets and at least one chain at the second end of at least one of the elastically deformable members; PA1 the means converting the rotation of the rotary control member into an action of stressing or relaxing the elastically deformable members may additionally comprise two screw-and-nut connecting members, each connecting the second end of the corresponding elastically deformable member to the chassis; PA1 the said cylindrical gear wheels at the second end of at least one of the elastically deformable members may couple the corresponding screw-and-nut connecting member to the rotary control-transmitting spindle; PA1 the said sprockets and the said chain(s) at the second end of at least one of the elastically deformable members may couple the corresponding screw-and-nut connecting member to the rotary control-transmitting spindle; PA1 at the second end of one of the elastically deformable members there may be two cylindrical gear wheels which couple the corresponding screw-and-nut connecting member to the rotary control-transmitting spindle and at the second end of the other elastically deformable member there may be two sprockets and a chain or three cylindrical gear wheels which couple the corresponding screw-and-nut connecting member to the rotary control-transmitting spindle; PA1 each screw-and-nut connecting member may have a screw member and a nut member, the said screw member or the said nut member being connected to the chassis so that it can only turn; PA1 the screw member may be formed of a threaded rod which is guided in rotation in the chassis without the possibility of translational movement and the nut member may be connected to the second end of the corresponding elastically deformable member; PA1 each elastically deformable member may comprise at least one cylindrical coil spring; PA1 the said cylindrical coil spring(s) may be (a) tension spring(s); PA1 the nut member may be formed of a nut screwed into the end of (one of) the cylindrical coil spring(s) of the corresponding elastically deformable member, the said nut having a threaded hole into which the threaded rod of the corresponding screw member is screwed; PA1 the rotary control member may be connected directly to the rotary control-transmitting spindle; PA1 the rotary control member may have a rotary control spindle which is at least approximately colinear with the rotary control-transmitting spindle; PA1 the rotary control spindle and the rotary control-transmitting spindle may form a single piece; PA1 the rotary control member may have a cranking handle extending to outside the chassis; PA1 the cranking handle may extend at one of the longitudinal ends of the chassis; PA1 the cranking handle may extend, viewed in the direction of forward travel during work, at the left-hand end of the chassis; PA1 each elastically deformable member may act on the harvesting mechanism by means of a rocker arm guided in rotation in the chassis and to which the first end of the said elastically deformable member is connected directly or indirectly, and a linkage extending between the rocker arm and the corresponding end of the harvesting mechanism; PA1 the suspension device connecting the harvesting mechanism to the chassis may comprise, in particular, two lower links each articulated between one end of the harvesting mechanism and the chassis, and each linkage may be articulated to the harvesting mechanism at a point in such a way that the tensile load exerted by the linkages creates, about the articulation about which the lower links are articulated to the harvesting mechanism, a moment which tends to raise the front of the harvesting mechanism; PA1 the chassis may comprise a hollow part extending transversely to the direction of forward travel during work and the elastically deformable members may extend at least approximately entirely inside the said hollow part of the chassis.
2. Discussion of the Background
A document, FR 2,110,911, is known in the prior art and describes such a mower which, broadly speaking, comprises a chassis, a connecting means for connecting the said chassis to a motor vehicle, a harvesting mechanism, a suspension device connecting the said harvesting mechanism to the chassis, a device for lightening the said harvesting mechanism and a centralized device for adjusting the lightening force exerted on the said harvesting mechanism.
The lightening device is associated with the harvesting mechanism and comprises a hydraulic ram for acting thereon by means of two cables and elastically deformable members so as to lighten the said harvesting mechanisms by exerting an upwardly-directed load on it. Each cable is actually associated with one elastically deformable member so as firstly, when the hydraulic ram lengthens, to lighten the harvesting mechanism and, secondly, when the said hydraulic ram lengthens further, to raise the said harvesting mechanism.
This known mower does, however, have a certain number of disadvantages.
Specifically, the hydraulic ram is controlled by the hydraulic unit of the motor vehicle, which unit does not allow the said hydraulic ram to be lengthened or shortened with sufficient precision. Furthermore, the slightest leak from the hydraulic ram or from the hydraulic circuit controlling it results in a variation in the length of this ram, and this results in a change of the lightening of the harvesting mechanism.